From: Ben Bolker <bolker_at_ufl.edu>

Date: Sun, 23 Nov 2008 13:06:42 -0500

*>
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> You are absolutely right - but when you look at the example, I want

*> that the FINAL latin hypercube sets sum up to one, and the values
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*> RANGING from 0 to 1, i.e. (0.5, 0.5) would also satisfy the condition.
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*>
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*>
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> Probably both - but to try again:

*>
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*> 1) values ranging between 0 and 1 (0 <= x <= 1)
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*> 2) all elements in one set of the lLatin Hypercube should add to one.
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*>
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*> Assuming two dimensions, (1,0) & (0,1) & (0.3, 0.7) , ... would all
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*> satisfy the condition 1 and 2;
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*>
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*> (0.8, 0.3) would satisfy 1, but not 2;
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*> (-1, 2) would satisfy 2, but not 1
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*>
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*> Hope this clarifies my question,
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*>
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*> Rainer
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*>
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*>
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*>
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*>
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Date: Sun, 23 Nov 2008 13:06:42 -0500

x2 <- (x-min(x))/(max(x)-min(x)) ## establishes criterion 1

x3 <- x2/sum(x2) ## establishes criterion 2

work? I haven't thought about this very carefully, but since transformation makes min(x)=0 and max(x)=1 (and therefore sum(x)>1 -- although it won't work if length(x)<2 or var(x)==0) transformation 2 will necessarily reduce the range and therefore not violate criterion 1 ... ?

Ben Bolker

Rainer M Krug wrote:

> On Sun, Nov 23, 2008 at 7:43 PM, Ben Bolker <bolker@ufl.edu> wrote:

>> Rainer M Krug <r.m.krug <at> gmail.com> writes: >> >>> Hi >>> >>> I want to du a sensitivity analysis using Latin Hypercubes. But my >>> parameters have to fulfill two conditions: >>> >>> 1) ranging from 0 to 1 >>> 2) have to sum up to 1 >>> >> Perhaps I'm missing something, but it seems that there's >> only one vector that satisfies these two conditions simultaneously, >> which is x={0,1} ... ??? (Actually, technically speaking >> you could have as many zeros as you wanted -- x = {0,0,0,1} >> would also work -- but I don't think that's going to help much.) >> If min(x)=0 and max(x)=1, then x must contain 0 and 1. If x >> contains any other non-zero values, and no negative >> ones, then sum(x)>1 ...

> You are absolutely right - but when you look at the example, I want

>> You seem to have a problem either in your definitions, >> or in your communication of those definitions to us ...

> Probably both - but to try again:

>> cheers >> Ben Bolker >> >> ______________________________________________ >> R-help_at_r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >>

-- Ben Bolker Associate professor, Biology Dep't, Univ. of Florida bolker_at_ufl.edu / www.zoology.ufl.edu/bolker GPG key: www.zoology.ufl.edu/bolker/benbolker-publickey.asc ______________________________________________ R-help_at_r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.Received on Sun 23 Nov 2008 - 18:08:55 GMT

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